Electrophotographic printing system including a plurality of electrophotographic printers having adjustable printing speeds

Abstract

An electrophotographic apparatus system or an electrophotographic apparatus provided according to the present invention has the discrepancy of printing speed between tandem and single printing removed. The electrophotographic apparatus system or the electrophotographic apparatus is provided with printing speed changeover means 23a, 23b, 24 not only to select a printing speed applicable for the case where printing is effected with a plurality of electrophotographic apparatus A, B operatively linked together and another printing speed serviceable for the case where printing is implemented with each of plural electrophotographic apparatus put into separate run independently of one another, but also to shift the printing speeds from one to another, whereby the electrophotographic apparatus system or the electrophotographic apparatus may provide normal performance in each of the respective formations of printing.

What is claimed is: 
     
       1. An electrophotographic system, comprising: a first electrophotographic apparatus including a first preheater which is in contact with a conveyed recording material, for preheating the recording material, and first fixing means, disposed downstream of said first preheater in a recording material conveyance direction, for fixing a toner image formed on said recording material onto the recording material;   a second electrophotographic apparatus including a second preheater which is in contact with a conveyed recording material, for preheating the recording material, and second fixing means disposed downstream of said second preheater in a recording material conveyance direction, for fixing a toner image formed on said recording material onto the recording material; and   a printing speed change-over unit that selects a first printing speed when said first and second electrophotographic apparatuses are operatively independent from each other for printing operation, and for setting a temperature of said second preheater to a temperature equal to or lower than the glass transition point of toner and selecting a second printing speed lower than said first printing speed when said first and second electrophotographic apparatuses are operatively linked together for printing operation.   
     
     
       2. An electrophotographic apparatus as claimed in claim 1, wherein each of said first and second fixing means comprises a plurality of fixing rolls for pressing the toner on said recording material, wherein, in the process of fixing the toner on the recording material by said fixing rolls for the case where printing is effected with said plurality of electrophotographic apparatuses operatively linked together, at the forefront electrophotographic apparatus, a toner image formed on the printing material is fixed thereto via the process of preheating by said preheater and the process of heating/pressing by said plurality of fixing rolls, and at the subsequent electrophotographic apparatus, a toner image formed on the printing paper is fixed thereto through the process of preheating by said preheater set at the temperature less than the glass transition point of toner and the process of heating/pressing by said plurality of fixing rolls. 
     
     
       3. An electrophotographic apparatus as claimed in claim 1, wherein each of said first and second fixing means comprises a plurality of fixing rolls for pressing the toner on said recording material and wherein, in the process of fixing for the case where printing is effected with said plurality of electrophotographic apparatus operatively linked together, there takes place the following at the forefront electrophotographic apparatus, a toner image formed on a printing material is fixed thereto via the process of preheating by said preheater and the process of heating/pressing by said plurality of fixing rolls, and at the subsequent electrophotographic apparatus, a toner image formed on the printing material is fixed thereto via only the process of heating/pressing by said plurality of fixing rolls.